<!DOCTYPE html>
<html>
<head>
<style>
.slr {
  writing-mode: sideways-lr;
}
</style>
</head>
<body>
 <div>
  <div style="height:0px;width:0px;overflow:visible">
    <div style="height:100px;width:120px;background:rgba(0,255,0,0.8);display:inline-block;margin-top:200px;"></div>
  </div>
  <div style="height:0px;width:0px;overflow:visible">
    <div style="height:100px;width:150px;background:rgba(255,0,0,0.8);display:inline-block;margin-top:100px;"></div>
  </div>
  <div class="slr" style="background:silver; height:calc(100vh - 16px);">
    <div style="margin-bottom:calc(100vh - 116px); direction:rtl">This text should appear ABOVE the green and red blocks.</div>
  </div>
 </div>
</body>
</html>
